Harrison, 19, won 67 percent of his service points and broke his opponent three times.

He next faces 29-year-old Mardy Fish, who beat World No. 68 Somdev Devvarman of India 6-4, 6-3 to reach his fourth ATP semifinal of the year.

Fish, the World No. 9, was effective on his first serve, winning 81 percent of those points, but he won only five points when he had to hit a second serve. Fortunately for the American, he got 73 percent of his first serves in.

Saturday’s match between the two Americans will be their first career encounter.